Insulin-dependent diabetes mellitus (Type I) occurs in about 0.5% of Caucasians. The incidence increases over 20-fold in individuals with the specific susceptibility gene HLA-DQ3.2. Approximately 70% of individuals who become insulin-dependent diabetics carry this gene, making it the most specific genetic marker known for identifying individuals at risk. Clearly this is a significant risk factor for screening, however, standard methods are inadequate for routine screening and identification of the DQ3.2 gene. DNA oligonucleotide probes have been used in Southern blots with genomic DNA to identify the DQ3.2 gene, and to discriminate it from closely related, non-diabetogenic alleles. In this work, DNA oligonucleotide probes will be used in a nylon bead based sandwich hybridization assay for detecting the DQ3.2 gene in human lymphocytes. Hybridization with target DQ3.2 gene will be detected using a chemiluminescent signal system. Procedures will be developed for the rapid detection of the DQ3.2 gene with high specificity and sensitivity. The long-term objectives are development of a product for the detection of genetic predisposition to Type I diabetes, and of a rapid and sensitive nylon bead sandwich assay technology for the detection of additional genetic markers.